# US 11,993,688 B2 · Molded article of carbon fiber composite material and production method for molded article of carbon fiber composite material

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- Number: US 11,993,688 B2
- Document ID: US11993688B2
- Status: Granted
- Kind: B2
- Application number: 17/435,200
- Filed: 2020-03-25
- Published: 2022-05-12
- Granted: 2024-05-28
- Earliest claimed: 2019-03-28
- Assignees: Toray Industries, Inc.
- Applicants: Toray Industries, Inc.
- Inventors: Hideto Mitsuoka; Yuji Ozeki
- Web page: https://patentgrep.com/patent/US11993688B2

## CPC

- B29C 70/00: Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- C08J 5/243: {using carbon fibres}
- B29C 33/68: Release sheets
- B29C 65/48: using adhesives {, i.e. using supplementary joining material; solvent bonding}
- B29C 66/028: {Non-mechanical surface pre-treatments, i.e. by flame treatment, electric discharge treatment, plasma treatment, wave energy or particle radiation (B29C65/14 takes precedence; non-mechanical surface treatment of plastics in general B29C59/08 - B29C59/16)}
- B29C 66/30322: {in the form of rugosity}
- B29C 66/71: {characterised by the composition of the plastics material of the parts to be joined (welding bar compositions B29C65/125)}
- B29C 66/7212: {characterised by the composition of the fibres}
- B29C 66/72143: {Fibres of discontinuous lengths}
- B29C 66/7392: {characterised by the material of at least one of the parts being a thermoplastic}
- B29C 66/7394: {characterised by the material of at least one of the parts being a thermoset}
- B29C 66/742: {to metals or their alloys}
- B29C 70/42: for producing articles of definite length, i.e. discrete articles
- B29C 71/009: {using gases without chemical reaction (C08J7/12 takes precedence; in combination with blow-moulding B29C49/46; surface treatment using plasma B29C59/14, ionised gas B29C59/16)}
- B32B 5/024: {Woven fabric}
- B32B 5/263: {next to one or more woven fabric layers}
- B32B 7/12: using interposed adhesives or interposed materials with bonding properties
- B32B 15/085: comprising polyolefins
- B32B 15/18: comprising iron or steel {(B32B15/011, B32B15/012 and B32B15/013 take precedence)}
- B32B 27/12: next to a fibrous or filamentary layer
- B32B 27/32: comprising polyolefins {(comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30)}
- C08J 5/042: {with carbon fibres}
- C08J 5/128: {Adhesives without diluent}
- C08J 7/123: {Treatment by wave energy or particle radiation (C08J7/18 takes precedence)}
- B29C 33/60: Releasing, lubricating or separating agents {(in general C10M)}
- B29C 65/8215: {Tensile tests}
- B29C 70/46: using matched moulds, e.g. for deforming sheet moulding compounds [SMC] or prepregs
- B29K 2063/00: Use of {EP, i.e.} epoxy resins {or derivatives thereof}, as moulding material
- B29K 2105/0881: {unidirectional}
- B29K 2307/04: Carbon
- B32B 2260/021: Fibrous or filamentary layer
- B32B 2260/046: Synthetic resin
- B32B 2262/106: Carbon fibres, e.g. graphite fibres
- B32B 2307/538: Roughness
- B32B 2307/542: Shear strength
- C08J 2323/12: Polypropene
- C08J 2323/20: having four to nine carbon atoms
- C08J 2327/12: containing fluorine atoms
- C08J 2345/00: Characterised by the use of homopolymers or copolymers of compounds having no unsaturated aliphatic radicals in side chain, and having one or more carbon-to-carbon double bonds in a carbocyclic or in a heterocyclic ring system; Derivatives of such polymers
- C08J 2463/00: Characterised by the use of epoxy resins; Derivatives of epoxy resins
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS

## Abstract

A molded article of a carbon fiber composite material includes at least carbon fibers and a resin composition. The molded article of a carbon fiber composite material is characterized in that the surface roughness Ra thereof is 0.01-2 μm and in that the tensile shear adhesive strength (F0) thereof when a metal has been adhered to the surface thereof via an adhesive layer that contains an epoxy compound and is 0.1-3 mm thick is 10-40 MPa.

## Claims

### Claim 1

A molded article of a carbon fiber composite material including at least a carbon fiber and a resin composition, wherein
the molded article has a surface roughness Ra of 0.01 μm or more and 2 μm or less, and
a tensile lap-shear strength (F0) is 10 MPa or more and 40 MPa or less when the molded article is bonded with a metal with an adhesive layer formed on a surface of the molded article being interposed therebetween, the adhesive layer containing an epoxy compound and having a thickness of 0.1 mm or more and 3 mm or less on a surface thereof, and
a ratio {γp/γd} between a surface free energy dispersion component (γd) and a surface free energy polar component (γp) constituting the surface free energy (γTOTAL) is 0 or more and 1 or less, and
the molded article has a surface free energy (γTOTAL) of 49 mJ/m2 or more and 80 mJ/m2 or less, and
a ratio {O/C} of the number of atoms of oxygen (O) with respect to the number of atoms of carbon (C) on the surface of the molded article of the carbon fiber composite material, measured by X-ray photoelectron spectroscopy, is 0.4 or more and 1.2 or less.

### Claim 2 (depends on 1)

The molded article according to claim 1, wherein a ratio {F/C} of the number of atoms of fluorine (F) with respect to the number of atoms of carbon (C) on a surface of the carbon fiber composite material, measured by X-ray photoelectron spectroscopy, is 0 or more and 0.5 or less.

### Claim 3 (depends on 1)

The molded article according to claim 1, wherein an intensity ratio {X/M} of a peak (X) attributed to C—O and C—N with respect to a main peak (M) in a narrow scan with deconvoluted C1s peaks obtained by measurement on a surface of the molded article by X-ray photoelectron spectroscopy is 0.4 or more and 0.8 or less.

### Claim 4 (depends on 1)

The molded article according to claim 1, wherein an intensity ratio {Y/M} of a peak (Y) attributed to C═O with respect to a main peak (M) in a narrow scan with deconvoluted C1s peaks obtained by measurement on a surface of the molded article by X-ray photoelectron spectroscopy is 0.1 or more and 0.3 or less.

### Claim 5 (depends on 1)

The molded article according to claim 1, wherein an intensity ratio {Z/M} of a peak (Z) attributed to C(═O)—O with respect to a main peak (M) in a narrow scan with deconvoluted C1s peaks obtained by measurement on a surface of the molded article by X-ray photoelectron spectroscopy is 0.1 or more and 0.3 or less.

### Claim 6 (depends on 1)

The molded article according to claim 1, wherein
the carbon fiber has an average diameter of 1 to 20 μm, and an average length of 10 mm or more, and
a content of the carbon fiber contained in the carbon fiber composite material is 5 to 75 vol %.

### Claim 7 (depends on 1)

The molded article according to claim 1, wherein the resin composition contained in the molded article of the carbon fiber composite material is a thermosetting resin composition containing an epoxy resin.

### Claim 8 (depends on 1)

The molded article according to claim 1, wherein a ratio {F11/F0} of a tensile lap-shear strength (F0) and a tensile lap-shear strength (F11) measured after wet heat treatment is 0.80 or more and 1 or less.

### Claim 9 (depends on 1)

The molded article according to claim 1, further comprising a bonded body in which metal is bonded to the surface of the molded article with an adhesive containing an epoxy compound.

### Claim 10 (depends on 9)

The molded article according to claim 9, wherein a ratio {F11/F0} of a tensile lap-shear strength (F0) and a tensile lap-shear strength (F11) measured after wet heat treatment is 0.80 or more and 1 or less.

### Claim 11 (depends on 1)

The molded article according to claim 1, wherein the ratio {γp/γd} is 0.3 or more and 1 or less.

### Claim 12 (depends on 1)

A method of producing the molded article according to claim 1 by molding the carbon fiber composite material, comprising the step of press-molding,
wherein a release agent containing a fluorine element or a release film containing a fluorine element is used in the press-molding.

### Claim 13 (depends on 12)

The method according to claim 12, further comprising the step of subjecting the surface of the carbon fiber composite material to plasma treatment after press-molding.